# Best Available Retrofit Technology Analysis

Con solidated Edison Company of New York, Inc.
59 th 

# Street Station and Ravenswood Steam Plant

Prepared for:

Con solidated Edison Company of New York, Inc.

4 Irving Place New York, NY 10003

Prepared by:

T RC Environmental Corporation 1200 Wall Street West, 2 nd 

### Floor Lyndhurst, NJ 07071

September 201059 th Street Station and Ravenswood Steam Plant BART Analysis

i TABLE OF CONTENTS

Section Page

E XECUTIVE SUMMARY

... ...................................... ........................................iii 1.0 INTRODUCTION

................................ ................................ ................................ .............. 1 1.1 59 th Street Station

................................ ................................ ................................ ............. 2 1.2 Ravenswood Steam Plant

................................ ................................ ................................ . 3 2.0 CONTROL TECHNOLOGY ANALYSIS

................................ ................................ ...... 5 2.1 Approach Used in BART Analysis

................................ ................................ .................. 5 2.1.1 Available Retrofit Control Technology

................................ ................................ ........ 5 2.1.2 Costs of Compliance

................................ ................................ ................................ ..... 5 2.1.3 Energy and Non

- Air Quality Environmental Impacts of Compliance

.......................... 7 2.1.4 Pollution Control Equipment in Use at the Source

................................ ....................... 8 2.1.5 Remaining Useful Life of the Source

................................ ................................ ........... 8 2.1.6 Degree of Improvement in Visibility Which May Reasonably be Anticipated to Result from the Use of Such Technology

................................ ................................ ............................ 8 2.1.7 BART Analysis

................................ ................................ ................................ ............. 8 2.2 BART Analysis for NO x ................................ ................................ ................................ ... 9 2.2.1 Available Retrofit Control Technology

................................ ................................ ...... 10 2.2.2 Costs of Compliance

................................ ................................ ................................ ... 14 2.2.3 Energy and Non

- Air Quality Environmental Impacts of Compliance

........................ 15 2.2.4 Pollution Control Equipment in Use at the Source

................................ ..................... 16 2.2.5 Remaining Useful Life of the Source

................................ ................................ ......... 16 2.2.6 Degree of Visibility Improvement

................................ ................................ .............. 16 2.2.7 BART Proposal

................................ ................................ ................................ ........... 17 2.3 BART Analysis for SO 2
................................ ................................ ................................ . 17 2.3.1 BART Proposal

................................ ................................ ................................ ........... 17 2.4 BART Analysis for PM

- 10

................................ ................................ ............................. 17 2.4.1 Available Retrofit Control Technology

................................ ................................ ...... 18 2.4.2 Polluti on Control Equipment in Use at the Source

................................ ..................... 20 2.4.3 Remaining Useful Life of the Source

................................ ................................ ......... 20 2.4.4 BART Proposal

................................ ................................ ................................ ........... 20 3.0 VISIBILITY MODELING

................................ ................................ .............................. 21 3.1 Visibility Model

................................ ................................ ................................ ............. 21 3.2 Receptor Locations

................................ ................................ ................................ ......... 21 3.3 Meteorological Databases

................................ ................................ .............................. 22 3.4 Visibility Index, Thresholds and CALPOST Processing

................................ ............... 26 3.5 Modeling Results

................................ ................................ ................................ ............ 2659 th Street Station and Ravenswood Steam Plant BART Analysis

ii LIST OF TABLES

Table 2

- 1 Summary of Cost

- Effectiveness of Technologically Feasible NO x Control Options Table 2

- 2 Summary of Cost

- Effectiveness of Technologically Feasible SO 2 Control Options Table 3

- 1 Con Edison

- 59th Street Pre

- Controls

- BART Class I CALPUFF Impacts Table 3

- 2 Con Edison

- 59th Street Post

- Controls

- BART Class I CALPUFF Impacts Table 3

- 3 Con Edison

- Ravenswood Pre

- Controls

- BART Class I CALPUFF Impacts Table 3

- 4 Con Edison

- Ravenswood Post

- Controls

- BART Class I CALPUFF Impacts

LIST OF FIGURES

Figure 3

- 1 Vermont Modeling Domain and Class I Areas F i gure 3

- 2 AECOM Modeling Domain and Class I Areas

LIST OF APPENDICES

Appendix A Emission Calculations Appendix B Summary of BACT/LAER Determinations Appendix C BART Cost Analyses Appendix D NYSDEC Modeling Protocol Appendix E Modeling Input and Output F iles59 th Street Station and Ravenswood Steam Plant BART Analysis

iii EXECUTIVE SUMMARY

In response to increased adverse visibility impacts at Class I “pristine” air quality areas due to existing major sources, the U.S. Environmental Protection Agency (EPA) promulgated the Best Available Retrofit Technology (BART) rul es in 1999 and issued an updated Regional Haze Rule
in 2005. For states with Class I areas, and for states that contain eligible stationary sources which may cause or contribute to regional haze issues in Class I areas contained in downwind states, EPA re quires the implementation of measures to reduce emissions of these visibility

impairing pollutants. While New York State contains no Class I areas, it has been identified as containing sources eligible for BART which contribute to the regional haze issue in Class I areas
in other states.

In order to be subject to BART, sources : (1) must have the potential to emit 250 tons per year or more of a visibility

- impairing pollutant (VIP), namely nitrogen oxides, particulate matter less
than 10 microns or sulfur dioxide; (2) were put in place between August 7, 1962 and August 7,
1977 ; and (3) whose operations fall within one or more of 26 specifically listed categories.
Fossil

- fuel fired boilers with a maximum heat input of more than 250 million British thermal

un its per hour (MMBtu/hr) are one of the 26 listed BART source categories. As per notification by the New York State Department of Environmental Conservation ( NYSDEC )

, Boilers #114
and #115 located at the 59 th Street Station and Boiler #2 at the Ravenswood Steam Plant are subject to BART. Sources subject to BART are required to submit their five

- factor analysis of potential BART controls to the NYSDEC by October 1, 2010

.

A BART analysis was prepared for the three subject boilers based upon consideration of five statutory factors required by the Clean Air Act (CAA). These factors for available retrofit control technologies are: (1) the costs of compliance; (2) the energy and non

- air quality environmental impacts of control options; (3) any pollution contr ol equipment in use at the source (which affects the availability of options and their impacts); (4) the remaining useful life of the source; and (5) the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology.

The CALPUFF model was used to evaluate visibility impacts of present emissions from the 59 th

Street Station Boilers #114 and #115 and the Ravenswood Steam Plant Boiler #2 and BART
control alternatives at the following seven Class I areas:

B rigantine Lye Brook
Acadia Presidential Range59 th Street Station and Ravenswood Steam Plant BART Analysis

iv Great Gulf Dolly Sods ; and
Otter Creek.

T he maximum and 98% percentile (or Highest 8th H ighest , H8H ) 24

- hour visibility impact for the pre

- and post

- BART control sourc e emissions for each Class I Area w ere det ermined

. A summary of the visibility modeling results is provided in Section 3.0.

A control technology analysis has been performed for the 59 th Street Station Boiler #114 and Boiler #115 and the Ravenswood Steam Plant Boiler #2 in accordance with guida nce presented in 40 CFR Part 51 and Appendix Y to 40 CFR Part 51 as well as guidance provided by NYSDEC. To identify retrofit control technology options for the subject equipment, a search of the U.S. EPA’s RACT/BACT/LAER Clearinghouse (RBLC) was performe d for each VIP. For the purposes of determining dollar

- per

- ton cost

- effectiveness of each technologically feasible control option, capital and O&M costs were based on order

- of

- magnitude vendor and consultant
estimates. C osts analyses based on these estim ates are provided in Appendix C.

Following is a summary of the conclusions of this analysis:

In accordance with NYSDEC guidance, the presumptive BART limit for oil fired units regardless of size is limiting the sulfur content of the oil fired to 1% by we ight or less.
The 59 th Street Boilers #114 and #115 and the Ravenswood Steam Plant Boiler #2 have permit conditions which limit the maximum sulfur content of the fuel oil to 0.3% by weight. Since the units ’ sulfur content limit is significantly below the p resumptive BART
limit for SO 2 , no additional SO 2 controls were considered in this analysis.

Based upon guidance provided by NYSDEC, the threshold cost for determining whether a particular control technology is cost effective is $5,500/ton. The cost

- eff ectiveness for all technically feasible NO x controls applied to the Ravenswood Steam Plant Boiler #2 are greater than $5,500/ton. Therefore, adding NO x controls to the Ravenswood Steam Plant
Boiler #2 is cost

- prohibitive.

While the $/ton of NO
x removed for water injection on the 59 th Street Boilers #114 and
#115 is slightly less than $5,500/ton, these values are based on the assumption that the units operate continuously (8,760 hours/year). Boilers #114 and #115 are steam

- only boilers that do not produ ce electricity . These boilers follow Con Edison’s Steam System
load changes

, which results in their limited operation and significant unused capacity.59 th Street Station and Ravenswood Steam Plant BART Analysis

v Further, the baseline NO x emissions were calculated using the maximum 24

- hour NO x emission rate since 2 005. When calculating the $/ton of NO
x removed based on actual historical operation, the cost effectiveness for all control technologies is greater than the $5,500/ton feasibility threshold. Therefore, additional NO
x controls on these units are
considere d cost

- prohibitive.

No add

- on controls for PM appear to be demonstrated effective in practice for a utility boiler that burns fuel oil as the primary fuel. Therefore, t he existing PM emission limits achieved through proper operation and maintenance of th e boilers

, as well as the use of
low sulfur residual oil

, are proposed as BART for the 59 th Street Station Boilers #114 and
#115 and the Ravenswood Steam Plant Boiler #2.59 th Street Station and Ravenswood Steam Plant BART Analysis

1 

### 1.0 INTRODUCTION

In Section 169A of the Clean Air Act (CAA), Congress declared as a na tional goal the prevention of any future, and remedying of any existing, visibility impairment in Federal Class I areas resulting from man

- made pollutant emissions. For states with Class I areas, and for states that contain eligible stationary sources whic h may cause or contribute to regional haze issues in Class I areas contained in downwind states, the United States Environmental Protection Agency (EPA) requires the implementation of measures to reduce emissions of these visibility

- impairing pollutants. While New York State contains no Class I areas, it has been identified as containing sources eligible for Best Available Retrofit Technology which contribute to the regional haze issue in Class I areas in other states. Accordingly, 6 NYCRR Part 249, "Best Available Retrofit Technology (BART)", was promulgated to ensure that proper advances will be made in fulfilling the goals of the CAA. The visibility

- impairing pollutants (VIPs) have been identified as particulate matter less than or equal to 10 microns in diameter (PM

- 10 ), sulfur dioxide (SO 2 ), and nitrogen oxides (NO x ).

To avoid confusion with other CAA requirements which also use the term "major stationary source" to refer to a somewhat different population of sources, the regional haze rule uses the

t erm "BART

- eligible source" to describe these sources. The BART

- eligible sources are those
sources which : (1) have the potential to emit 250 tons per year or more of a VIP ; (2) were put in place between August 7, 1962 and August 7, 1977 ; and (3) whose oper ations fall within one or more of 26 specifically listed source categories. BART

- eligible sources may be required to apply emissions control technology to reduce emissions of VIPs if such emissions are demonstrated to cause an adverse visibility impact at the nearest Class I areas. The major recommendations for BART visibility impact modeling and application of emissions controls are:

1. Identify BART

- eligible sources (based on date of operation, potential emissions of VIPs and facility source category)
2. Ide ntify which pollutants have greater than EPA

- suggested de minimis emissions levels
3. Identify sources that are subject to BART
4. Identify baseline visibility impact of each BART source
5. Identify feasible controls and emission changes

6. Identify the change in visi bility impact for each candidate BART control option
7. Compare the visibility improvement of BART control options to other statutory factors in the engineering analysis59 th Street Station and Ravenswood Steam Plant BART Analysis

2 BART

- eligible b oilers at t he 59 th Street Station and the Ravenswood Steam Plant are each very large boilers classified in the fossil

- fuel boilers of more than 250 million British thermal units per hour ( MMBtu /hr) heat input BART category. As per notification by NYSDEC

, units located at
the 59 th Street Station and Ravenswood Steam Plant that meet the date eligibility criteria (August 7, 1962

– August 7, 1977) and that have the potential to emit greater than 250 tons per year of at
least one of the VIPs are as follows.

 59 th Street Station Boiler #114

 59 th Street Station Boiler #11 5

 Ravenswood Steam Plant Boiler #2

Sources subject to BART are required to submit their five

- factor analysis of potential BART
controls to the NYSDEC by October 1, 2010. Control equipment or other emission reduction methods approved as BART must be installed and oper ating no later than January 1, 2014. If an applicable source chooses not to comply with the provisions of Part 249, it must permanently shut down operations by January 1, 2014. This report satisfies the requirement to submit a BART analysis by October 1, 2010.

1.1 59 th Street Station

As stated above, the BART

- eligible sources at the 59 th Street Station are Boiler s # 114 and #115

. Both boilers are Combustion Engineering fixed

- tangential boilers installed i n 1966. E ach has a design maximum heat input capacity of 805 MMBtu /hr. Boilers #114 and #115 are steam

- only boilers that do not produce electricity and follow steam load which results in limited operation and significant unused capacity. Both units burn low sulfur No. 6 fuel oil (0.3% sulfur by weight) as t he primary fuel with natural gas being used for ignition. NO x emissions from each
boiler are controlled with the use of off

- stoichiometric firing. The boilers are subject to NO x RACT and currently have a presumptive NO x RACT limit of 0.25 lb/ MMBtu . Con Edison complies with NO x RACT under a system

- averaging plan. Particulate matter emissions from
Boiler # 114 and Boiler # 115 are limited to 0.1 lb/ MMBtu (filterable PM only) in the facility’s Title V Operating Permit and demonstrate compliance by stack test ing once per permit term

.

T he maximum annual potential emissions of VIPs from 59 th Street Station Boiler # 114 and
Boiler # 115 (per unit) are as follows:

 NO x – 1057.8 tons/year

 SO 2 – 1107.1 tons/year59 th Street Station and Ravenswood Steam Plant BART Analysis

3  PM

- 10

– 387.8 tons/year (filterable + condensable PM

- 10 )

Since potential emissions of NO x , SO 2 and PM

- 10 fr om Boiler s # 114 and #115 each exceed 250 tons/year, emissions of NO x , SO 2 and PM

- 10 are addressed in this BART analysis

.

Actual short

- term emissions of filterable PM

- 10 were determined using the results of the most recent stack test performed in 200 7 for the 59 th Street Station boilers

. Condensable PM emissions were calculated using AP

- 42 emission factors for fuel oil combustion. Actual short
term emissions of SO 2 were based upon AP

- 42 emission factors and the maximum sulfur content for fuel oil deliveries over the past five years. Actual annual emissions of NO x , SO 2 and PM

- 10 were based upon the average gallons of No. 6 fuel oil burned in the boilers over calendar years
200 7 through 2009 . Potential an d actual emission calculations are presented in detail in Appendix A.

1.2 Ravenswood Steam Plant

As stated above, the BART

- eligible source at the Ravenswood Steam Plant is Boiler #2

. Boiler
#2 is a front wall fired boiler and was installed in 19 6 2. This un it was manufactured by Babcock
and Wilcox and has a design maximum heat input capacity of 424 MMBtu /hr. Boilers #2 is a

steam

- only boiler that does not produce electricity and follows steam load which results in limited operation and significant unused ca pacity. This unit burns low sulfur No. 6 fuel oil (0.3% sulfur by weight) as the primary fuel with natural gas being used for ignition. Boiler #2 is subject to NO x RACT and has a presumptive NO x RACT limit of 0.25 lb/ MMBtu . Con Edison complies with NO x RACT under a system

- averaging plan.

T he maximum annual potential emissions of VIPs from Boiler #2 are as follows:

 NO x – 510.7 tons/year

 SO 2 – 583.1 tons/year

 PM

- 10

– 204.3 tons/year

Since potential emissions of NO x and SO 2 from Boiler #2 each exceed 2 50 tons/year, emissions
of all VIPs ( NO x , SO 2 and PM

- 10 ) must be addressed in this BART analysis

.

Actual short

- term emissions of filterable PM

- 10 were determined using the results of the most recent stack test performed in 200 8. Condensable PM emissions were calculated using AP

- 42
emission factors for fuel oil combustion. Actual short term emissions of SO 2 were based upon59 th Street Station and Ravenswood Steam Plant BART Analysis

4 AP

- 42 emission factors and the maximum sulfur content for fuel oil deliveries over the past five years. Actual annual emissions of NO x , SO 2 and PM

- 10 were based upon the average gallons of No. 6 fuel oil burned in the boilers over calendar years 2007 through 2009. Potential and actual emission calculations are presented in detail in Appendix A.59 th Street Station and Ravenswood Steam Plant BART Analysis

5 

### 2.0 CONTROL TECHNOLOGY ANALYSIS

A control technology analysis has been performed for the 59 th Street Station Boiler # 114 and
Boiler # 115 and the Ravenswood Steam Plant Boiler #2 in accordance with guidance presented
in 40 CFR Part 51 and Appendix Y to 40 CFR Part 51 as well as guidance provided b y NYSDEC . Section 2.1 presents an overview of the f ive

- factor assessment procedure used in this analysis.

2.1 Approach Used in BART Analysis

The determination of BART must be based on an analysis of the best system of continuous
emission control technolo gy available and associated emission reductions achievable for each
BART

- eligible source that is subject to BART. 40 CFR Subpart 51.302 and guidance presented in Appendix Y to 40 CFR Part 51 states that the BART analysis must be based upon
consideration o f five statutory factors required by the Clean Air Act (CAA) to determine the appropriate level of control for BART. These factors for available retrofit control technologies are: (1) the costs of compliance; (2) the energy and non

- air quality environment al impacts of control options; (3) any pollution control equipment in use at the source (which affects the availability of options and their impacts); (4) the remaining useful life of the source; and (5) the degree of improvement in visibility which may re asonably be anticipated to result from the use of such technology.

2.1.1 Available Retrofit Control Technology

T o identify retrofit control technology options for the subject equipment, a search of the U.S. EPA’s RACT/BACT/LAER Clearinghouse (RBLC) has been pe rformed. Individual searches have been performed for each subject pollutant (NO x , SO 2 and PM

- 10) emitted from each emissions unit. Results of the RBLC search are summarized in Appendix B.

2.1.2 Costs of Compliance

The cost of compliance factor involves cal culation of the cost

- effectiveness of each control technology option on a dollar per ton of pollution removed basis. Annual emissions with a control option are subtracted from baseline annual emissions to calculate tons of pollutants controlled per year. Annual costs , in dollars per year

, are calculated by adding annual operation and maintenance costs to the annualized capital cost of an option (amortized over ten years)

.59 th Street Station and Ravenswood Steam Plant BART Analysis

6 Cost

- effectiveness ($/ton) of an option is simply the equivalent annual cost ($/yr) divided by the annual pollution controlled (ton/yr). The facility can also calculate incremental costs when several control technology options with varying levels of emission control effectiveness are
available.

Note that no economic analysis is require d if either the most effective option is proposed or if there are no technically feasible control options. When required in the evaluation of technically feasible options, the cost

- effectiveness evaluation is based on engineering estimates, vendor quotati ons, internal cost estimates and cost estimation guidelines presented in the January 2002 U.S. EPA guidance document “OAQPS Control Cost Manual, Sixth Edition” (EPA 452/B

- 02

- 001).

The economic portion of the BART consists of a comparison of the annualiz ed cost of each option to the annual emission reduction it can produce, represented as dollars per ton. The annualized cost of each option has two components: the annualized total capital investment and the annual operating and maintenance cost.

The Tota l Capital Investment (TCI) is the sum of the total direct costs (TDC) and total indirect costs. Direct costs are defined as the capital investment required to purchase equipment needed for the control system. Examples of direct costs include purchased equ ipment costs (PEC) and
installation. Indirect costs include vendor engineering costs, costs for administration and supervisions, taxes and interest

.

The PEC for technically feasible control technologies are primarily based upon vendor quotations , Con E dison internal cost estimates or estimates from USEPA

- published guidance
documents.

The capital recovery factor (CRF) is used to convert capital cost estimates into equivalent
annualized costs. T o annualize capital costs, an interest rate and project l ife must be estimated. When the CRF is multiplied by the capital investment, the product is the uniform end

- of

- year payment necessary to repay the investment in a defined amount of years. The CRF can be calculated based upon the following equation:

CRF = [i * (1+i) n ] / [(1+i) n

– 1]

Where: i = interest rate; and

n = number of years of the investment.59 th Street Station and Ravenswood Steam Plant BART Analysis

7 An 8% nominal interest rate has been selected for this evaluation. The investment life, n, has been assumed equal to a ten

- year payback period. These v alues are consistent with values presented in the OAQPS Control Cost Manual. Therefore, the TCI has been amortized over a

ten

- year period at an 8% interest rate.

The Total Annual Operating Cost is defined as the expenses associated with the annual opera tion of the control equipment and is the sum of direct annual costs and indirect annual costs. Direct annual costs include operating and supervisory labor, maintenance labor and materials required to operate the control equipment. Examples of direct annu al costs are maintenance labor associated with the up

- keep of the control equipment, parts, costs for raw materials and catalyst replacement, and utility costs. Indirect annual costs include overhead, property taxes, insurance and administration (includin g environmental reporting) associated with the operation of the control equipment.

Specific costing factors for feasible alternatives are identified in the appropriate pollutant

specific section. For the purposes of determining dollar

- per

- ton cost

- effe ctiveness of the technologically feasible control equipment, emission reductions have been calculated based upon
vendor estimates for an option compared to the base case emissions. Results of the cost analyses are included in Appendix C.

2.1.3 Energy and Non

- A ir Quality Environmental Impacts of Compliance

The energy requirements of the control technology are examined. An assessment is made on whether the use of that technology results in energy penalties or benefits. If such benefits or penalties exist, they are quantified in this step to the extent practicable. Because energy penalties or benefits can usually be quantified in terms of additional cost or income to the source, the energy impacts analysis can, in most cases, simply be factored into the cost im pacts analysis.

The primary focus of the environmental impact analysis is the reduction in ambient concentrations of the pollutant being emitted. Increases or decreases in emissions of other
criteria or non

- criteria pollutants may occur with some techn ologies, and should also be
identified. Non

- air impacts, such as solid waste disposal, increased water consumption/treatment and irreversible or irretrievable commitment of resources, should be identified/quantified if they are an issue for the project co ntrol options.59 th Street Station and Ravenswood Steam Plant BART Analysis

8 2.1.4 Pollution Control Equipment in Use at the Source

A source may already be using an emission control device to control emissions of VIPs. Use of an existing control device can be considered to represent the baseline emissions. Replacement of the existing control device with a more efficient control technology or improving the existing control technology can also be considered in the case

- by

- case BART analysis.

2.1.5 Remaining Useful Life of the Source

The BART source’s “remaining useful life” may be considered as one element of the overall cost analysis. The “remaining useful life” of a source, if it represents a relatively short time period, may affect the annualized costs of retrofit controls. The remaining useful life is the difference
bet ween:

(1) the date that the proposed BART emission controls will be put in place (capital

and other construction costs incurred before controls are put in place can be rolled into the first year, as suggested in U.S. EPA’s OAQPS Control Cost Manual); and

(2) th e date the facility permanently stops operations. Where this affects the BART determination, this date should be assured by a federally

- or State

- enforceable restriction preventing further operation.

This BART analysis does not incorporate the remaining useful life of the BART

- eligible sources into the cost analysis. However, the remaining useful life of the BART

- eligible sources is
discussed.

2.1.6 Degree of Improvement in Visibility Which May Reasonabl y be Anticipated to Result from the Use of Such Technol ogy

As appropriate, to complete the BART a ssessment , an impact analysis was conducted to
determine the visibility improvement expected as a result of adding the various control technologies. Comparisons were made of the pre

- control visibility impacts bas ed on existing conditions to those anticipated to result from installing add

- on control equipment.

2.1.7 BART Analysis

From the alternatives evaluated in the above

- listed steps, the facility developed a chart displaying
for each of the alternatives:59 th Street Station and Ravenswood Steam Plant BART Analysis

9 (1) expected emission rate (tons per year, pounds per hour); (2) emissions performance level (e.g., percent pollutant removed, emissions per unit product, lb/ MMBtu , ppm); (3) expected emissions reductions (tons per year); (4) costs of compliance

-- total annualized costs ($), cost effectiveness ($/ton), and incremental cost effectiveness ($/ton), and/or any other cost effectiveness measures (such as $/deciview 1 ); (5) energy impacts; (6) non

- air quality environmental impacts; and (7) modeled visibility impacts.

Control options are evaluated on the following basis:

(1) display the options evaluated; (2) identify the average and incremental costs of each option; (3) consider the energy and non

- air quality environmental impacts of each option; (4) consider the remaining useful life; and (5) consider the modeled visibility impacts.

The facility provides justification for adopting the technology selected as the "best" level of control, including an explanation of the CAA factors that differentiated between or among BART control options. Even if the control techn ology is cost effective, there may be cases where the installation of controls would affect the viability of continued plant operations.

2.2 BART Analysis for NO x

The formation of NO x is determined by the interaction of chemical and physical processes

occu rring within the furnace. There are two princip a l forms of NO x designated as “thermal” NO x and “fuel” NO x . Thermal NO x formation is the result of oxidation of atmospheric nitrogen contained in the inlet gas in the high

- temperature, post

- flame region of t he combustion zone. The major factors influencing thermal NO x formation are temperature, concentrations of nitrogen and oxygen in the inlet air and residence time within the combustion zone. Fuel NO x is formed by the oxidation of fuel

- bound nitrogen. NO x formation can be controlled by adjusting the

1 In the regional haze rule definition of deciview the EPA states: “A deciview is a haze index de rived from calculated light extinction, such that uniform changes in haziness correspond to uniform incremental changes in perception across the entire range of conditions, from pristine to highly impaired” (40 CFR §51.301).59 th Street Station and Ravenswood Steam Plant BART Analysis

10 combustion process and/or installing post

- combustion controls.

2.2.1 Available Retrofit Control Technology

A review of approximately 30 facilities with fuel oil

- fired boilers with maximum heat inputs greater tha n 250 MMBtu /hr listed in the U.S. EPA’s RBLC (see Appendix B) lists NO x emission limits ranging from 0. 06 to 0.730 lb/ MMBtu

. 59 th Street Boilers #114 and #115 and Ravenswood Boiler #2 are subject to NYSDEC Part 227

- 2 (NO x RACT) as very large boilers.
Ve ry large boilers currently have a presumptive NO x RACT limit of 0.25 lb/ MMBtu . Con Edison complies with NO x RACT through a system

- wide averaging plan. The maximum 24

- hour NO x emission rate over the last five years of operation for the 59 th Street Boilers #114 and
#115 is 0. 3 0 lb/ MMBtu with an average 24

- hour NO x emission rate of 0.209 lb/ MMBtu . The
maximum 24

- hour NO x emission rate over the last five years of operation for Ravenswood Steam
Plant Boiler #2 was 0.275 lb/ MMBtu

, with an average 24

- hour NO x e mission rate of 0.21
lb/ MMBtu

.

NO x emission controls listed in the RBLC for fuel oil

- and/or natural gas

- fired boilers with maximum heat inputs greater than 250 MMBtu /hr are:

 Low NO x Burners

 Ultra Low NO x Burners

 Water Injection

 Flue Gas Recirculation

 Selective Catalytic Reduction

 Selective Non

- Catalytic Reduction

Although not listed in the U.S. EPA’s RBLC, the facility has identified the following additional
NO x emission control devices for fuel oil

- fired boilers with maximum heat inputs greater than
250 MMBtu /hr:

 Overfire Air

Low and Ultra Low NO x Burners

Low NO x Burners (LNB) control NO x formation by carrying out the combustion in stages. These burners control the combustion staging at and within the burner rather than in the firebox. This

contr ol is achieved through design features which regulate the aerodynamic distribution and59 th Street Station and Ravenswood Steam Plant BART Analysis

11 mixing of fuel and air. By staging the combustion process, thermal NO x formation is reduced by lowering the peak flame temperature. In addition, fuel NO x formation is reduced by lowering the amount of oxygen in the initial combustion zone. Ultra Low NO x Burners (ULNB) control NO x in the same manner as described above

.

The oil atomizers and burner swirlers on the 59 th Street Boilers #114 and #115 have been
modified t o a low NO x design. No additional reduction is expected by the installation of LNBs
on the 59 th Street boilers. The oil atomizers and burner swirlers on Ravenswood Steam Plant
Boiler # 2 have also been modified to a low NO x design. However, t he installa tion of LNB on
the Ravenswood Steam Plant boiler is considered a technologically feasible retrofit op tion.
Based on vendor information, a maximum of 15% NO x reduction is anticipated with the installation of LNB. ULNBs, however, are not compatible with he avy oil firing, therefore, they are not considered further in this analysis as a technically feasible option.

Overfire Air

In the Overfire Air (OFA) process, the injection of air into the firing chamber is staged into two zones. The staging of the com bustion air reduces NO x formation by two mechanisms. The staged combustion results in a cooler flame. In addition, the staged combustion also results in less oxygen reacting with fuel molecules. The degree of staging is limited by operational problems s ince the staged combustion results in incomplete combustion conditions and the staged combustion results in a longer flame.

The installation of OFA on the boilers is cons idered a technologically feasible option. OFA is estimated to provide approximately 20% NO x reduction for 59 th Street Boilers #114 and #115
and 25 % NO x reduction below the current baseline NO x emissions for the Ravenswood Steam
Plant Boiler #2

.

Selective Non

- Catalytic Reduction

Selective Non

- Catalytic Reduction (SNCR) involves the react ion of ammonia radicals, produced from the reaction of injected NH 3 with radicals present in the hot flue gas, to reduce nitric oxide (NO) to nitrogen (N 2 ). The ammonia radicals can also be produced by the injection of urea. The reactions for SNCR are pr esented below:

For ammonia: 4NH 3 + 4NO + O 2 => 4N 2 + 6H 2 O +heat
For urea: 2(NH 2 ) 2 CO + 4NO + O 2 => 4N 2 + 4H 2 O + 2CO 2 + heat59 th Street Station and Ravenswood Steam Plant BART Analysis

12 The reactions presented above are predominant in the temperature range between 1,600

- 2, 2 00 F.

Based on the high temperature range required for the reaction to remove NO x emissions, an SNCR would need to be located inside the combustion chamber of the subject boilers. The
installation of SNCR is feasible for the 59 th Street boilers, but will be difficult to implement. There is limited access to suitable injector locations and very limited residence time for the
chemical reactions to occur. The limited res idence time and injector accessibility would limit the
NO x reduction capabilities to ap proximately 20%. Similar to 59 th Street, t he installation of
SNCR is considered a technologically feasible option for the Ravenswood Steam Plant Boiler #2, but will be difficult to implement due to the limited access to suitable injector locations and the

very short residence time. SNCR for B oiler #2 is estimated to provide approximately 20 % NO x reduction

.

Water Injection

Water injection involves injecting micronized water droplets into the NO x production zones of a gas burner flame. The use of water injection only treats thermal NO x . NO x reductions up to 10% have been demonstrated on heavy oil fired tangentially fired boilers, however there have been mixed results on heavy oil wall fired boilers.

The use of water injection is considered a technica lly feasible control option for 59 th Street Boilers #114 and #115. Water injection has not been demonstrated to provide reliable NO x reduction for the Ravenswood Steam Plant Boiler #2.

Flue Gas Recirculation

Flue Gas Recirculation (FGR) controls NO x by recycling a portion of cold flue gas back into the primary combustion zone. The recycled air lowers NO x emissions by two mechanisms; ( 1) the recycled gas is made up of combustion products which act as inerts during combustion, thereby lowering combustion temperatures and ( 2) by lowering the oxygen content in the primary flame zone. The amount of recirculation is based on flame stability. Typically, 1 5 % to 20% of the total flue gas is recycled.

Two approaches are commonly used to inject the FGR into the combustion air. Forced FGR uses a separate fan (FGR fan) to inject the flue gas into the combustion air downstream of the FD fan. The second approach uses the suction of the FD fan to induce flue gas from the exhaust duct,59 th Street Station and Ravenswood Steam Plant BART Analysis

13 through the FD fan, and into the windbox (induced FGR). The installation of FGR on all of the
boilers is considered a technologica lly feasible option. Induced FGR is lower in cost and provides the same percentage NO x reduction, therefore, only IFGR is considered further in this analys is.

Based on vendor data, FGR is estimated to provide approximately 1 0 % NO x reduction below the
current baseline NO x emissions for the 59 th Street Boilers #114 and #115 and 10% NO x reduction
for the Ravenswood Steam Plant Boiler #2.

Selective Cataly tic Reduction

Selective Catalytic Reduction (SCR) involves the injection of diluted ammonia (NH 3 ) into the exhaust gas stream upstream of a catalyst bed. On the catalyst surface, ammonia reacts with NO x contained within the air to form molecular Nitrogen (N 2 ) and water (H 2 O).

4NH 3 + 4NO + O 2 => 4N 2 + 6H 2 O
8NH 3 + 6NO 2 => 7N 2 + 12H 2 O

It is important to have stable operations and uniform flue gas temperatures to achieve optimum

NO x control. The catalyst exhibits optimum performance in a temperature rang e within +/

- 50 F.
Outside of this optimum range, the effectiveness of this catalyst is greatly reduced.

The temperature range for standard SCR operations is between 5 5 0

- 80 0 F. Since the SCR system is a post combustion control device, it would need to be located downstream from the
combustion chamber of the boiler.

The installation of SCR is considered a technologically feasible option for both Stations

. Due to the configuration of the 59 th Street Station units, implementing SCR on the boilers would present many challenges. The boilers would need to be reducted/reconfigured. These challenges result in extremely high costs. The Ravenswood Steam Plant has a very small footprint. The SCR module would need to be installed on the boiler building roof. The roof would need to be reinforced with steel to support the SCR module, resulting in a high capital cost. Based on
discussions with a NO x emission control technology vendor, SCR is estimated to provide approximately 4 7 % NO x reduction below the current baseline NO x emissions for the subject
boilers.59 th Street Station and Ravenswood Steam Plant BART Analysis

14 2.2.2 Costs of Compliance

Based upon the assumptions presented in Section 2.1.2, cost of compliance analysis, on a $/ton basis, has been provided for technically feasible control equipment described in Section 2.2.1. A summary of the cost

- effectiveness of each of the control devices evaluated is presented in Table
2

- 1. A detailed cost analysis is presented in Appendix C.

Table 2

- 1 Summary of Cost

- Effectiveness of Technologically Feasible NO x Control Options

BART

Eligible
Source Control Potential
Annual NO x Emission Rate (TPY) Average

Actual Annual
NO x Emission
Rate
2007

- 2009 (TPY) NO x

Emission
Reduction
Performance (%) Total

Annualized
Cost Cost

Effectiveness
based on 8,760 hrs/yr ($/ton) Cost

Effectiven ess based on expected
annual operation ($/ton)
59 th Street
Boiler #114
and #115 SCR 2116 817 47% $ 8,738,399 $8,788 $22,747

SNCR 20% $4,076,000 $9,633 $24,934

Water Injection 10% $712,490 $3,368 $8,717

OFA 20% $2,803,113 $6,625 $17,147

FGR 1 0 % $2,601,209 $12,296 $31,825

Ravenswood
Steam Plant
Boiler #2 SCR 511 83 47% $3,457,287 $14,403 $88,310

SNCR 20 % $ 2

, 192

, 374 $ 21

, 464 $ 131

, 600

LNB 15% $1,897,018 $24,763 $151,828

OFA 25 % $3,867,963 $30,295 $185,743

FGR 10% $623,974 $12,218 $74,910

Based up on guidance provided by NYSDE C

, the threshold cost for determining whether a particular control technology is cost effective is $5,500/ton . The cost

- effectiveness for all technically feasible NO x control s applied to the Ravenswood Steam Plant Boiler # 2 are greater than $ 5 ,500/ton. Therefore, adding NO x controls to the Ravenswood Steam Plant Boiler #2 is

cost

- prohibitive.

While the $/ton of NO
x removed for water injection on the 59 th Street Boilers #114 and #115 is less than $5,500/t on, these values are based on the assumption that the units operate continuously (8,760 hours/year). Boilers #114 and #115 are steam only boilers that do not produce electricity and follow steam load which results in limited operation and significant unus ed capacity. For practical purposes, Boilers #114 and #115 have an average annual capacity factor of less than
60%. Further, the baseline NO x emissions were calculated using the maximum 24

- hour NOx59 th Street Station and Ravenswood Steam Plant BART Analysis

15 emission rate since 2005. When calculating the $/ton of NO x removed based on actual operation, the cost effectiveness for all control technologies are greater than the $5,500/ton feasibility threshold. Therefore, additional controls on these units are considered cost

- prohibitive.

2.2.3 Energy and Non

- Air Quality E nvironmental Impacts of Compliance

Low NO x Burners

Energy and non

- air quality environmental impacts of compliance for the use of LNB are
minimal.

Overfire Air

OFA involves using energy to power a fan that can inject air into the firing chamber of the b oiler. The boiler steam production has the potential to be reduced if there are any backpressure losses due to the OFA system. Also, the degree of OFA staging is limited by operational problems since the staged combustion results in incomplete combustion conditions and the staged combustion results in a longer flame thus burning more fuel.

Selective Non

- Catalytic Reduction

There are a dditional costs associated with purchasing ammonia or urea . There would be an energy penalty that would be required to t ransport the ammonia /urea from the storage tank into
the boiler. In addition, t here are also water requirements to either dilute the concentrated
ammonia or to mix with urea prior to injecting into the boiler

. Transporting the reagent would
also result i n increased emissions due to truck traffic.

Flue Gas Recirculation

FGR involves using energy to power a fan that can re

- inject a portion of cold flue gas back into the primary combustion zone. The boiler steam production has the potential to be reduced if there are any backpressure losses due to the FGR system.

Selective Catalytic Reduction

As described above for the SNCR system, t here are also additional costs associated with purchasing ammonia or urea and additional water usage/costs

. There would al so be an energy59 th Street Station and Ravenswood Steam Plant BART Analysis

16 penalty that would be required to transport the ammonia/urea from the storage tank into the
boiler and increased emissions from trucks transporting the reagent

. The SCR catalyst needs to be replaced every few years of operation. Replacing the catalyst causes the facility to have
increased solid waste.

An undesirable side

- effect of SCR is the potential formation of ammonium bisulfate (NH 4 HSO 4 ) and ammonium sulfate ((NH 4 ) 2 SO 4 ), referred to as ammonium salts, which are corrosive and can
sti ck to the heat recovery surfaces, duct work, or stack at low temperatures and results in
additional PM/PM

- 10 formation if emitted. NH 4 HSO 4 and (NH 4 ) 2 SO 4 are reaction products of
SO 3 and NH 3
.

2.2.4 Pollution Control Equipment in Use at the Source

59 th Street Boilers # 114 and # 115 and Ravenswood Steam Plant Boiler #2 are operated with good combustion/operating practices. In addition, the oil atomizers and burner swirlers on the 59 th

Street Boilers #114 and #115 have been modified to a low NO x design. The fac ilities employ a continuous emission monitoring system (CEMS) that measures NO x , O 2 and CO 2 to ensure that
the boiler s compl y with Con Edison’s system

- wide NOx RACT emission limit. Use of the CEMS system allows for the boiler operator to optimize combusti on and minimize emissions of
NO x and other pollutants.

2.2.5 Remaining Useful Life of the Source

The 59 th Street Station Boilers #114 and #115 were installed in 1966. The Ravenswood Steam
Plant Boiler #2 was installed in 1962. It is assumed that the normal u seful life of a utility boiler is between 30 and 60 years.

2.2.6 Degree of Visibility Improvement

An impact analysis was conducted to assess the visibility improvement of the various NO x controls. See Section 3 for detailed visibility modeling results. In summary, for the 59 th Street boilers, the only NO x control which resulted in a cost

- effectiveness less than $5,500/ton of NO
x removed (potential emissions basis) w as water injection (10% NO x control)

. Based on a
conservative 20% NO x reduction, the degree of visibility improvement ranged from 1.8% to 2.6% (using the 98 th percentile values) . This corresponds to a negligible visibility improvement from existing conditions.59 th Street Station and Ravenswood Steam Plant BART Analysis

1 7 2.2.7 Proposal for NO x BART Compliance

Based on actual operation of the boilers, the use of additional NO x controls is considered cost prohibitive. In addition to cost, there are additional energy requirements and non

- air quality environmental impacts associated with each of the NO x emission control technologies under
consideration . Further, the degree of visibility improvement as a result of employing these controls is negligible (< 3%). Therefore, n o additional NO x emission control technology is proposed. The boilers will continue to use good combustion/operating practices and low NO x oil atomizers and burner swirlers to comply with BART for NO x .

2.3 BART Analysis for SO 2

SO 2 emissions are formed from oxidation of sulfur in the fuel. Strategies for the control of SO 2 emissions can be divided into pre

- and post

- combustion categories. Pre

- combustion controls
entail the use of low

- sulfur fuels. Post

- combustion controls comprise various wet and dry flue gas desulfurization processes.

In accordance with NYSDEC guidance

, the presumptive BART limit for oil fired units regardless
of size is lim iting the sulfur content of the oil fired to 1% by weight or less. The 59 th Street
Boilers #114 and #115 and the Ravenswood Steam Plant Boiler #2 have permit condition s which limit the maximum sulfur content of the fuel oil to 0.3% by weight. Since the u nits sulfur
content limit is significantly below the p resumptive BART limit for SO 2 , no additional SO 2 controls were considered in this analysis.

2.3.1 Proposal for SO 2 BART Compliance

In accordance with NYSDEC guidance, the presumptive BART limit for oil fire d units regardless of size is limiting the sulfur content of the oil fired to 1% by weight or less. Therefore, t he existing maximum fuel oil sulfur content limit of 0. 3 % by weight is proposed as BART for the
59 th Street Station Boilers #114 and #115 and th e Ravenswood Steam Plant Boiler #2

.

2.4 BART Analysis for PM

- 10

PM

- 10 emissions may be categorized as either filterable or condensable. Filterable emissions are generally considered to be the particles that are trapped by the glass fiber filter in the front half of

a Reference Method 5 or Method 17 sampling train . Vapors and particles less than 0.3 microns pass through the filter. Condensable particulate matter is material that is emitted in the vapor state which later condenses to form homogeneous and/or het erogeneous aerosol particles. The59 th Street Station and Ravenswood Steam Plant BART Analysis

18 condensable particulate emitted from boilers fueled on coal or oil is primarily inorganic in nature.

Filterable particulate matter emissions depend predominantly on the grade of fuel fired. Combustion of lighter distill ate oils results in significantly lower PM formation than does combustion of heavier residual oils. Among residual oils, firing of No. 4 or No. 5 oil usually produces less PM than does the firing of heavier No. 6 oil.

In general, filterable PM emission s depend on the completeness of combustion as well as on the oil ash content. The PM emitted by distillate oil

- fired boilers primarily comprises carbonaceous particles resulting from incomplete combustion of oil and is not correlated to the ash or sulfur

c ontent of the oil. However, PM emissions from residual oil burning are related to the oil sulfur content. This is because low sulfur No. 6 oil, either from naturally low

- sulfur crude oil or desulfurized by one of several processes, exhibits substantially lower viscosity and reduced asphaltene, ash, and sulfur contents, which results in better atomization and more complete
combustion.

Boiler load can also affect filterable particulate emissions in units firing No. 6 oil. At low load (50 percent of maximum rating) conditions, particulate emissions from utility boilers may be lowered by 30 to 40 percent and by as much as 60 percent from small industrial and commercial units. However, no significant particulate emission reductions have been noted at low loads from boilers firing any of the lighter grades. At very low load conditions (approximately 30 percent of maximum rating), proper combustion conditions may be difficult to maintain and particulate emissions may increase significantly.

2.4.1 Available Retrofit Con trol Technology

A review of 1 9 facilities with fuel oil

- fired boilers having maximum heat inputs greater than 250
MMBtu /hr listed in the U.S. EPA’s RBLC (see Appendix B) lists PM

- 10 emission limits ranging
from 0.003 to 0.210 lb/ MMBtu

. The 59 th Street Bo ilers #114 and #115 and Ravenswood Steam
Plant Boiler #2 each employ good combustion practices and use of low sulfur residual oil to
minimize PM

- 10 emissions. Each facility has a Title V permit which limits PM emissions to 0.10
lb/ MMBtu . Stack testing per formed in 2007 for the 59 th Street Boilers show s that PM emissions are approximately half (0.056 lb/ MMBtu ) of the permitted emission limit of 0.10 lb/ MMBtu . In 2008 stack testing for PM was performed on the Ravenswood Steam Plant Boiler #2. Stack test

re sults indicate that actual PM emissions are significantly less (0.025 lb/ MMBtu ) than the permitted emission limit of 0.10 lb/ MMBtu

.59 th Street Station and Ravenswood Steam Plant BART Analysis

19 PM

- 10 emission controls listed in the RBLC for fuel oil

- fired boilers with maximum heat inputs greater than 250 MMBtu /hr ar e:

 Electrostatic Precipitator

 Fabric Filter/Baghouse

 Cyclone

Electrostatic Precipitator

An Electrostatic Precipitator (ESP) is a particulate control device that uses electrical forces to move particles entrained within an exhaust stream onto collection surfaces. The entrained particles are given an electrical charge when they pass through a corona, a region where gaseous ions flow. Electrodes in the center of the flow lane are maintained at high voltage and generate
the electrical field that forces the particles to the collector walls. In dry ESPs, the collectors are knocked, or “rapped”, by various mechanical means to dislodge the particulate, which slides downward into a hopper where they are collected. The hopper is evacuated periodically, as it
be comes full. Dust is removed through a valve into a dust

- handling system, such as a pneumatic conveyor, and is then disposed of in an appropriate manner.

The boilers listed in the RBLC as having ESP systems all are designed and operate to primarily
burn c oal, waste fuels and/or wood waste. Since this control technology does not appear to be demonstrated in practice for a utility boiler that burns fuel oil as the primary fuel, it is not considered any further in this analysis

.

Fabric Filter/Baghouse

In a fabric filter, flue gas is passed through a tightly woven or felted fabric, causing PM

- 10 in the flue gas to be collected on the fabric by sieving and other mechanisms. Fabric filters may be in the form of sheets, cartridges, or bags, with a number of th e individual fabric filter units housed together in a group. Bags are the most common type of fabric filter. The dust cake that forms on the filter from the collected PM can significantly increase collection efficiency. Fabric filters are frequently ref

erred to as baghouses because the fabric is usually configured in cylindrical bags. Bags may be 6 to 9 m (20 to 30 ft) long and 13 to 31 centimeters (cm) (5 to 12 inches) in diameter. Groups of bags are placed in isolable compartments to allow cleaning o f the bags or replacement of some of the bags without shutting down the entire fabric filter.59 th Street Station and Ravenswood Steam Plant BART Analysis

20 The boilers listed in the RBLC as having fabric filters or baghouse systems all are designed and operate to primarily burn coal, waste fuels and/or wood waste. Since this control technology does not appear to be demonstrated in practice for a utility boiler that burns fuel oil as the primary fuel, it is not considered further in this analysis

.

Cyclone

Cyclones use inertia to remove particles from the gas stream . The cyclone imparts centrifugal force on the gas stream, usually within a conical shaped chamber. Cyclones operate by creating a double vortex inside the cyclone body. The incoming gas is forced into circular motion down the cyclone near the inner sur face of the cyclone tube. At the bottom of the cyclone, the gas turns and spirals up through the center of the tube and out of the top of the cyclone. The use of cyclones to control PM

- 10 emissions from utility boilers that primarily burn fuel oil and/or natural gas is not specifically listed in the records of the RBLC.

2.4.2 Pollution Control Equipment in Use at the Source

59 th Street Boilers #114 and #115 and Ravenswood Steam Plant Boiler #2 ea ch employ good combustion practices and use of low sulfur residu al oil to minimize PM

- 10 emissions.

2.4.3 Remaining Useful Life of the Source

The 59 th Street Station Boilers #114 and #115 were installed in 19 66. The Ravenswood Steam
Plant Boiler #2 was installed in 1962 . It is assumed that the normal useful life of a ut ility boiler is between 30 and 60 years.

2.4.4 Proposal for PM

- 10 BART Compliance

The add on control technologies identified above do not appear to be demonstrated in practice for a utility boiler that burns fuel oil as the primary fuel. Therefore, t he exis ting PM emission limits achieved through proper operation and maintenance of the boiler as well as the use of low sulfur
residual oil are proposed as BART for the 59 th Street Station Boiler s # 114 and # 115 and the
Ravenswood Steam Plant Boiler #2

.59 th Street Station and Ravenswood Steam Plant BART Analysis

21 

### 3.0 VISIBILI TY MODELING

Visibility modeling was performed to assess the impacts from three Con Edison sources

- the
59th Street Station Boilers 114 and 115 , and B oiler #2 at the Rave nswood Steam Plant

– at seven Class I areas. These seven Class I areas are : Briganti ne, Lye Brook, Acadia, Presidential Range, Great Gulf, Dolly Sods and Otter Creek.

The “default recommendations” of the NYSDEC Guidance And Protocol For Visibility Modeling Of Bart Eligible Sources, Final: February 25, 2010 were followed.

3.1 Visibility Mod el

As recommended in the NYSDEC protocol, this analysis was performed with the regulatory version 5.8 of the CALPUFF modeling system . The model was used to assess atmospheric dispersion and in

- transit chemistry to e stimate visibility impairment f r om the Con Edison BART

sources in New York. T he model was run twice: once for pre

- control and once for post

- control. This allows the net improvement of the BART controls to be determined, by comparing the pre

and post

- control scenarios.

T he EPA/FLM “default” model options were used within this analysis for the various parameters
in the CALPUFF model runs

.

Due to the large number of grid cells in the AECOM domain 2 , CALPUFF version 5.8 was recompiled with the Lahey

- Fujitsu Fortran compiler version 7.1 to accep t the parameters in the CALMET dataset. This executable is included with the modeling files.

3.2 Receptor Locations

As directed by the protocol, the standard receptor locations for each of the seven Class I areas
were downloaded from the National Park Servi ce (NPS) Air Resource s Division website. ( http://www.nature.nps.gov/air/maps/Receptors/index.cfm ).

The receptors are created by the National Park Service, and are placed approximately one kilometer apart. Depending on the size of the Class I area, the rec eptors are then extracted to

2 The AECOM dataset incorporate s the MANE

- VU MM5 wind field data as well as NWS observations. This dataset was more refined in all 3 dimensions, being based upon a 4 kilometer grid cell spacing, with 11 vertical layers. It included 263 grid cells in the X direction, and 325 grid cells in the Y direction.59 th Street Station and Ravenswood Steam Plant BART Analysis

22 every second, every third or every fourth receptor in an effort to keep the number of receptors between 100 and 1000 per area.

The receptor locations are received in Latitude/Longitude coordinate format from the National
Park Service. To be used within the model, they must be converted to a Lambert Conical Conformal (LCC) coordinate system appropriate to each of the two pre

- processed CALMET meteorological databases provided by NYSDEC.

It should be noted that, even though th e protocol suggests its use, the NPS conversion program is inappropriate to use in this case without additional conversions. When converting from the default Lat/Lon coordinates to a LCC coordinate system, the NPS program forces the output into
the NWS84 datum, also known as the NWS 6370KM Radius, Sphere datum.

In contrast, the Vermont CALMET dataset is in WGS

- G datum, or the WGS

- 84 GRS 80 Spheroid, Global coverage (WGS84) datum. And the AECOM CALMET dataset is in NAS

- C datum, or the NORTH AMERICAN 192 7 Clarke 1866 Spheroid, MEAN FOR CONUS (NAD27) datum.

If the receptor locations are converted in the NPS program only and placed within the two CALMET coordinate systems, an approximate five (5) kilometer east

- west offset, or error, in the receptor locati ons will occur. The receptor locations within the Vermont CALPUFF/CALMET analysis, as provided on hard drive by the NYSDEC, contain this discrepancy.

This issue was discussed with Margaret Valis of the NYSDEC

- Air Resource Division by email.
She direct ed TRC to make certain that the receptor LCC datum matches the datum of the CALMET datasets to ensure that the correct receptor coordinates are used in the analysis.

Therefore the conversion process was accomplished by using the “CALPUFF Coords”
conversio n program. This program allows the user to select the LCC output datum, such that it matches the datum used in the other stages of CALPUFF/CALMET.

3.3 Meteorological Databases

As suggested by the protocol, two pre

- processed CALMET datasets were received on a hard drive from the NYSDEC for this study. This was the Vermont CALMET dataset, and the AECOM CALMET dataset, both from the 2002 calendar year.59 th Street Station and Ravenswood Steam Plant BART Analysis

23 T he VT DEC CALMET dataset utilized National Weather Service me teorological observations only (i.e. radioson de measurements for the upper atmospheric representation, Automated Surface Observing Station (ASOS) for the surface, and precipitation observers’ measurements). This dataset is based upon thirty six (36) kilometer grid cells spacing, with 74 grid cells i n the X direction, and 60 grid cells in the Y direction, and eight (8) vertical layers. See Figure 3

- 1.

The second CALMET dataset, provided by NYSDEC, was the AECOM dataset. This data incorporates the MANE

- VU MM5 wind f ield data, as well as NWS observat ions discussed in the previous paragraph. This dataset was more refined in all 3 dimensions, being based upon a 4 kilometer grid cell spacing, with 11 vertical layers. It included 263 grid cells in the X direction, and 325 grid cells in the Y direction. However, it does cover a smaller geographic extant. See Figure 3

- 2.59 th Street Station and Ravenswood Steam Plant BART Analysis

24 Figure 3

- 1

– Vermont Modeling Domain and Class I Areas59 th Street Station and Ravenswood Steam Plant BART Analysis

25 Figure 3

- 2

– AECOM Modeling Domain and Class I Areas59 th Street Station and Ravenswood Steam Plant BART Analysis

26 3.4 Visibility Index , Thresholds and CALPOST Processing

As recommended in the protocol, the CALPUFF model runs were post processed to obtain the following results:

1) T he maximum and 98% percentile (or Highest 8th H ighest , H8H ) 24 hour visibility impact for the pre and post BART control sourc e emissions for each Class I Area, fro m both the 59 th Street and Ravenswood facilities

. 2) The impacts calculated in #1 also provide the individual contribution of Sulfates (SO 4 )

, Nitrates (NO 3 ) and particulate emissions (PMC + PMF), on a percentile basis

. 3) T he number of days of visibility impac ts , at each Class I Area, which exceed a deciview value of 0.1, 0.5 and 1.0 for the pre and post BART control source from both the 59 th

Street and Ravenswood facilities

.

In addition, th ese visibility impacts were calculated relative to the 20% best days natural background levels, at each of the seven Class I Areas, as defined by the Federal Land Managers
within the draft 2008 FLAG revised document

.

Also in accordance with the 2008 FLAG revised document, the “new” IMPROVE equation used
for extinction coefficient calculations was used. This was accomplished by using CALPOST version 6.221, which contains the new equations. The default Method 8 “FLAG 2008” options were selected within the post processing.

As with the CALPUFF executable, the CALPOST exe cutable had to be recompiled with the LF Fortran compiler, to allow for the large domain used within the AECOM CALMET dataset. This executable is included with the modeling files.

3.5 Modeling Results

The modeling results are presented in the following tabl es:59 th Street Station and Ravenswood A House BART Proposal

27 Table 3

- 1 ConEdison

- 59th Street Pre

- Controls

- BART Class I CALPUFF Impacts59 th Street Station and Ravenswood A House BART Proposal

28 Table 3

- 2 ConEdison

- 59th Street Post Controls

- BART Class I CALPUFF Impacts

Note: Post control case corresponds to a 20% NO
x reduction.59 th Street Station and Ravenswood A House BART Proposal

29 Table 3

- 3 ConE dis on

– Ravenswood Pre

- Controls

- BART Class I CALPUFF Impacts59 th Street Station and Ravenswood A House BART Proposal

30 Table 3

- 4 ConEdison

– Ravenswood Post Controls

- BART Class I CALPUFF Impacts

Note: Post control case corresponds to a 30% NO
x reduction.59 th Street Station and Ravenswood Steam Plant BART Analysis

31

### APPENDIX A

EMISSION CALCULATION S

### APPEND IX B

SUMMARY OF BACT/LAER DETERMINATIONS

### APPENDIX C

BART COST ANALYSES

### APPENDIX D

NYSDEC MODELING PROTOCOL1 Guidelines for BART determination under the Regional Haze Rule , Appendix Y to Part 51; see final Preamble and BART Guidelines at: http://www.epa.gov/air/visibility/actions.html

2 http://www.nescaum.org/topics/regional-haze/regional-haze-documents 

### NYSDEC GUIDANCE AND PROTOCOL FOR VISIBILITY MODELING OF BART ELIGIBLE SOURCES

Final: February 25, 2010

I. Background. The federal Regional Haze Rule’s provisions for the determination of Best Available Retrofit Technology (BART) was finalized on June 15, 2005 1 and contains a requirement to assess the net visibility improvement for sources subject to BART, as one of five statutory factors in the determination of best control alternative for subject sources. The EPA BART Guidelines provide states considerable flexibility in determining both the approach to be taken in the visibility assessment as well as in the associated determinations leading to the best option for choosing BART, but it nonetheless contains some general recommendations which have been incorporated in our approach. In addition to EPA’s guidance, the NESCAUM organization and the MANE-VU Regional Pla nning Organization have provided a number of documents and have performed a first level, yet comprehensive visibility assessment of the impact of BART eligible sources to regional haze at a set of Class I areas in the Northeast and mid-Atlantic states 2 . Specifically, certain aspects of the approach used in the document

“ Contribution to Regional Haze in the Northeast and Mid-Atlantic United States” , dated August 31, 2006, are used as the basis for the guidance provided herein.

EPA’s BART Guidelines recommend the development of a modeling protocol and provides some general items to be addressed in the visibility analysis approach. This protocol identifies a set of NYSDEC “default” recommendations to be used specifically for the modeling approach for BART sources in New York in order to calculate the net improvements in visibility at a set of Class I areas. These recommendations are based, in part, on the EPA guidance and NESCAUM documents noted previously, but have been further refined and updated to incorporated more recent EPA guidance on application of the CALPUFF/CALMET modeling package, as well as based on discussions with the involved agencies, including EPA Region 2, Vermont DEC, and the Federal Land Managers(FLMs) for Class I areas.

The list of BART eligible sources in New York were previously identified during the NESCAUM modeling exercise and subsequently finalized with the involved companies per the effected units. Originally, this protocol was developed for the non-EGU units from the list under the assumption that the CAIR regulations would serve as a sufficient surrogate for BART determined control measures. However, due to current uncertainty in the status of the CAIR rule, it has been determined that all eligible sources will have to undergo a BART review. In addition, while the NESCAUM regional study document “ Five Factor Analysis of BART Eligible Sources-Survey of Options for Conducting BART Determinations”, dated June 1, 2007 (at NESCAUM page in footnote 2) tentatively identifie d all of the eligible units as subject to BART3 Guidelines on Air Quality Models , Revised December 9, 2005, Appendix W of 40 CFR, Part 51.

4 http://www2.nature.nps.gov/air/permits/flag/index.cfm

5 http://www.epa.gov/ttn/scram/dispersion_prefrec.htm#calpuff

-2- based on the assumption that these have a significant contribution to or “cause” regional haze, the current protocol follows the BART rule in allowing “exemption modeling” for sources which could demonstrate visibility impacts below a relatively low threshold of 0.1deciviews per NYSDEC’s BART rule. All involved sources have already been notified that they must conduct the five factor BART analysis and present that information for NYSDEC review if the specific units are not exempted from the rule. In addition, concurrent with finalizing this protocol, facilities containing BART eligible units have been ask to provide updated emission rate and stack parameter information.

To assist in the modeling determination of the net improvement in visibility with the application of BART “alternatives” and in NYSDEC’ s incorporation of this factor in the overall BART determination, the following modeling approach and methodologies are recommended for use by BART eligible sources.

II. Visibility Modeling Methodology . This section identifies the model and its input and output requirements which NYSDEC has deemed acceptable, without a case specific modeling protocol, for the assessment of visibility impacts from sources subject to BART. These recommendations allow for consistent and equitable application of the visibility modeling using a “default” set of conditions which have been determined consistent with both EPA BART guidance and acceptable procedures. If a source chooses to deviate significantly from these procedures, then a source specific protocol must be submitted for NYSDEC review. In the latter case, adherence to recommendations in EPA’s Modeling Guidelines 3 and subsequent EPA clarification memos on CALPUFF and CALMET, as well as in the IWAQM report (proposed revised version, May 27, 2009) recommended in the BART Guidelines should be followed. These should also conform with recommendations from the the FLM’s Air Quality Related Values Workgroup(FLAG) in their revised June 27, 2008 document 4 . The following set of specific recommendations are made:

1) Visibility Model. Although the BART Guidelines and the NESCAUM report do not recommend a specific model for use in visibility assessment, they nonetheless note that the CALPUFF modeling system (with associated meteorological data and post processors) are an appropriate tool for such an assessment. Furthermore, EPA’s Modeling Guidelines recommend the CALPUFF model for long range transport assessments, such as for impacts at Class I areas. In addition, a large number of BART and similar Class I assessments have relied on the CALPUFF modeling results for decision making. Thus, the CALPUFF model (version 5.8, level 070623) 5 is recommended as the “default” model to be used in these visibility assessments, with the EPA/FLM “default” options set for the various parameters. The use of these default-3- settings will essentially simulate the conditions used in the NESCAUM assessments, with corrections for model code errors found in the previous versions. In addition, the CALMET/CALPUFF application for the NESCAUM regional haze study was based on an evaluation of certain of the model input parameters against observations, thus giving further weight to the final approach chosen. A c opy of an example CALPUFF input file has been obtained from Vermont DEC and will be provided to the sources.

In instances where a source would like to apply a model other than CALPUFF, a detailed modeling protocol should be submitted for DEC and EPA review prior to undertaking the BART visibility analysis. It should be recognized that in these cases, it will be necessary to demonstrate the appropriateness of the model for the specific application and to explain any deviations from current EPA guidance on model i nput and output processors. For example, the meteorological data input requirements as well as any post processing of visibility impacts must conform to the general recommendations in this document.

2) Receptors locations . The set of seven eligible non-EGU sources in New York which could be potentially subject to BART and which might have to perform a “net” visibility analysis are located in the upstate region of New York and in the generally upwind direction of the Class I areas in Vermont and New Hampshire. The BART guidelines notes that the nearest Class I area and any others in close proximity should be included in the analysis. For these non-EGU sources, the NESCAUM screening analysis indicated that all of the maximum visibility impacts occurred consistently at the Lye Brook area. Thus, it might be sufficient to model only the Lye Brook area since the White Mountain Class I area in New Hampshire is in the general downwind direction and at considerably further distance from these sources than the Lye Brook area. However, since a few of the EGU sources were found to maximize at the New Hampshire receptors, and since it will be informative to determine the level of improvement in visibility due to BART alternatives, the receptors in New Hampshire Class I areas as well as in all other areas noted for EGUs should be included in the analysis.

For the EGU sources, the NESCAUM modeling results indicated that the Class I area most impacted was the Brigantine Wilderness in New Jersey. In addition, two sources had maxima at the Acadia National Park in Maine, while one source in western New York maximized at the Dolly Sods Wilderness in West Virginia. Thus, for completeness and to provide potential visibility impact reductions at other than maximum impacted areas, all receptors in these and adjacent Class I areas defined below should be included in the modeling of both EGU and non-EGU units.

The BART guidelines indicate that receptors of sufficient density should be located at the nearest Class I area. The example Vermont DEC CALPUFF application file noted above contains a set of 103 receptors at Lye Brook whic h were developed with input from the National Park Service(NPS)/FLM. A set of receptors recommended for all of the Class I areas are6 See http://www.nature.nps.gov/air/maps/Receptors/index.cfm

7 Appendix D: Development of Parallel CALPUFF Dispersion Modeling Platforms for Sulfate Source Attribution Studies in the Northeast U.S. August 31, 2006. http://www.nescaum.org/documents/contributions-to-regional-h aze-in-the-northeast-and-mid-atlantic--united-states/

-4- available from NPS site 6 and should be used for the following Class I areas: Lye Brook, Acadia, Brigantine, Presidential Range, Great Gulf, Dolly Sods and Otter Creek. These receptors grids have been determine provide appropriate coverage of the individual Class I areas. A conversion program is also available at the NPS webpage in case the input to CALPUFF is desired in a format other than latitude/longitude.

3) Meteorological Data. Of major significance for the CALPUFF application are the set of surface and upper level meteorological data which are input through the CALMET processor to properly determine transport and dispersion conditions. The processing of such data is both resource intensive and technically challenging. The CALMET processed data used for the NESCAUM regional haze/sulfate source attribution analysis for BART eligible sources were developed using data for the year 2002 in two different “platforms”; one using NWS observations only by Vermont DEC and another using prognostic MM5 generated wind fields by University of Maryland, with certain non-wind surface observations for use by Maryland Department of Environment and with assistance from ERM consultants. Details of the meteorological data processing and application are provided in Appendix D 7 of the August 31, 2006 NESCAUM report. Both of the meteorological data sets used in the NESCAUM analysis were generated on a 12km grid and were further “refined” through a process which evaluated the set of CALMET variable settings against observations. For example, for the Vermont DEC application, comparisons were made betw een CALMET generated wind fields against observations at mid level of the boundary layer and radiosonde data. The particular settings which were deemed representative and were used in the final assessments are discussed and presented in Appendix D.

The two sets of CALMET generated data for the year 2002 did show differences in certain fields. This is not unexpected nor contrary to general findings with CALMET applications, given the differences in the met hods of data simulation and assimilation. However, there was no determination in the NESCAUM assessment as to which data base was preferred for CALPUFF applications, especially for a specific set of conditions such as New York BART sources and Class I areas of varying distances. Our original recommended approach was to use both data sets for the BART visibility assessments which would provide an “enveloped” analysis for the differences in wind fields associated with the two data sets.

Since our original recommendations at the end of 2007, EPA has undertaken a more rigorous review of the CALPUFF/CALMET mode ling approach for BART modeling. Based in part on this review, EPA set out recommendations specific to the grid resolution and the8 “Model Clearinghouse review of CALPUFF Modeling Protocol for BART ”. May 15, 2009 Memo from Tyler Fox to Kevin Golden of EPA Region 8 and May 27, 2009 draft revisions to IWAQM Phase 2 report.

9 “Clarification on EPA-FLM Recommended Settings for CALMET ”. August 31, 2009 memo from Tyler Fox to Regional EPA Modeling Contacts.

10 Comments on EPA’s proposed revisions to IWAQM Phase 2 report. Submitted by Dan Riley of Vermont DEC (available upon request).

-5- CALMET use of MM5 generated fields in a proposed revision to the IWAQM Phase 2 report 8

. In essence, the recommendation on grid resolution indicate that refinements to much lower grid resolution than used in the NESCAUM modeling (12km) or below a 4km spacing are not supported at this time. On the other hand, EPA noted that the use of CALMET with a “hybrid” mix of MM5 and NWS observation fields was th e preferred approach. Subsequently, however, EPA also indicated that certain of its previous recommendations needed further review based on initial CALMET performance evaluations which indicated performance deterioration under certain recommended settings 9 . The latter memorandum did identify a set of “default” settings for CALMET which are preferred by EPA and the FLMs.

Neither of the previously generated NESCAUM meteorological data bases for 2002 follow the specific recommendation of using a “hybrid” data base found in the latest EPA guidance. However, the guidance does indicate that an alternative approach to the “blending” of prognostic and observational data can be used if it has equal technical merit. In comments submitted by the State of Vermont on EPA’s proposed revisions to the IWAQM report 10 (supported by NESACUM states) background analyses on the use of “NWS observations only” CALMET data for the specific assessments for the Northeast visibility were provided. The analysis indicated good model performance using EPA’s IWAQM Phase 2 report’s statistical methods, especially in dealing with wind direction bias issues. Vermont’s review also pointed to previous findings as part of the NESCAUM’s me teorological data development (see footnote 6), indicating that the MM5 only data platform, which did not incorporated the observed wind fields, did have certain biases, except along the coastline. Given the performance re-evaluation conducted by Vermont DEC using EPA’s recent guidance and the additional evaluations EPA is still to undertake on their recommendation of using a “hybrid” data base, we have determined that the Vermont NWS only CALMET data base is still appropriate to be used as one of the data sets in the visibility analysis of New York BART sources. We understand that at this point EPA and FLMs do not consider this data as conforming to their latest guidance, but our purpose in recommending its use is again to envelope the set of meteorological conditions which could lead to the maximum impacts even with the same data year, barring any showing that the evaluation by Vermont DEC is inappropriate.

Since our initial modeling protocol at the end of 2007, a revised 2002 CALMET data base has been created which incorporates the MANE-VU MM5 wind field as well as NWS observations. This new data base is in accord with the latest EPA guidance and has been11 A Study of the Multiple Year Variation of Air Quality Impacts Predicted by the CALPUFF Dispersion Model. Paper no. 69232 by Daniel Riley of Vermont DEC. Can be provided upon request.

-6- reviewed and found appropriate by staff from the Fish and Wildlife Service. It covers all the Class I areas to be modeled for New York sources on a refined 4km grid basis. Details of the procedures used are provided in the attached AECOM consultants April, 2009 document. It is important to note that the acceptance of this one year data base by the FLMs is predicated on a set of conditions which have been incorporated herein. That is, in lieu of using the recommended three years of meteorological data for BART analysis, certain “conservative” steps must be undertaken in the review of impacts, as detailed below.

EPA’s modeling guidelines’ recommendation to use minimum of three years of meteorological data in assessing Class I area impacts in permitting actions allows the consideration of potential yearly variability in meteorological conditions in calculating expected worst case impacts. However, given the nature of the visibility thresholds to be used for these analysis, the level of importance that might be assigned to the modeling results as one of five criteria in BART determinations, and the practical constrains in meeting EPA deadlines for BART submissions, we conclude that specifi c BART analysis for New York sources can adequately rely on the revised AECOM’s hybrid MM5 and Vermont “NWS-only” data bases. On the other hand, the processing of additional years of data through the CALMET processor could potentially be required if a source chooses to deviate substantially from the recommendations in this protocol. We emphasize that, to the extent possible, the recommended setting for CALMET in EPA’s August 31, 2009 memo should be used in these BART analysis cases. In addition, in lieu of using three years of data, our review of the “best” BART alternative for each of the sources could also consider the effects of meteorological data variability on CALPUFF impacts using the results of an multi year data analysis of CALPUFF impacts conducted by Vermont DEC staff 11 . That analysis used five years (1990-1994) of meteorological data and provided average indicators of variab ility in impacts predicted by CALPUFF, including visibility, at the Lye Brook Class I area.

DEC has obtained both the Vermont and AECOM data bases for 2002 and will provide these to the BART sources. In order to obtain this data, sources will have to submit a 1terabite or larger external hard drive to NYSDEC staff.

4) Visibility Index, Thresholds and CALPOST Outputs . The NESCAUM analysis followed the BART Guidelines in relying on the deciview measure of visibility impacts and we recommend the same measure for the New York source specific analysis. As noted in the Regional Haze rule and BART guidelines, the deciview was developed to provide a visibility (or haziness) index which is linear with respect to perceived visual change and fractional change in12 “ Development and Application of a Standard Visual Index ”, Pitchford and Malm (1994), Atmospheric Environment , Vol.28, No.5, pp 1049-1054.

-7- extinction coefficient and is, thus, related to both these quantities 12 . Therefore, a change in visibility in terms of deciview can be related to other measures such as extinction coefficient preferred by the FLMs. As for comparison thresholds, the BART guidelines suggest certain deciview levels in terms of both exemption modeling and “cause” or “contribute” measures in BART determinations, but leave it to the state agency’s discretion to determine appropriate levels. As noted previously, New York has adopted a low 0.1dv level specifically for exemption modeling, but no other single measure has been set for source specific BART assessments. Thus, for any modeling to demonstrate a unit is exempt from any further assessments, a source can provide a showing that they meet the 0.1 dv level under existing conditions. In doing so, however, it is important to note that although EPA guidance allow the use of the 8 th highest impacts be used for this demonstration, this allowance is only acceptable if the analysis strictly relies on the appropriate modeling approach; for example, three years of meteorological data must be used. However, the FLMs have agreed to the use of the single 2002 year data by AECOM only to the extent that a) the maximum visibility impacts are used for comparison to the thresholds and b) the 20% best background conditions are used (see below).

For modeling to demonstrate the best BART alternative for a given unit, we have defined further criteria in order to fully understand the relevant impacts within the context of the five factors to be used for such determinations. That is, although we will use the maximum impacts to gauge the net improvements in visibility, we are also seeking a set of impacts from a source in order to get a more comprehensive understanding of these impacts in our BART determinations. As noted in the EPA BART guidelines, one “bright line” value might not be appropriate. We recognize that EPA has recommended levels at 1dv and 0.5dv for determination of “cause” and “contribute” in BART assessments, while the FLAG document has identified the corresponding “equivalent” extinction coefficient values for their decision making. Thus, instead of using a single threshold, we recommend the following CALPUFF post processing of visibility impacts to assist our determination of the best BART alternative for each source:

i) the maximum and 98% (or 8 th highest) 24 hour visibility impact for the pre and post BART control source emissions for each alternative.

ii) the number of days and the corresponding magnitude of visibility impacts which exceed a deciview value of 0.1, 0.5 and 1.0 for the pre and post BART control source emissions for each alternative.

iii) for facilities with more than one BART e ligible unit, the cumulative visibility maximum impacts of all units.

These impacts should provide the individual contribution of SOx, NOx and particulate emissions. The CALPUFF impact calculations must use the same scheme for the pre and post13 In a July 19, 2006 internal EPA memorandum from Joseph Paisie to Kay Prince of EPA Region 4, EPA clarified that it has given Stat es the choice between using the 20% best days or the annual average natural background levels for BART net visibility comparison purposes. However, we believe, for the same arguments set forth by NESCAUM, that the use of the 20% best values are appropriate for our BART determinations. This is especially true for comparisons of 24 hour visibility impacts.

14 Baseline and Natural Background Visibility Conditions , dated December, 2006, Prepared by NESCAUM and available on their webpage.

-8- control scenarios in all these calculations. In addition, these visibility impacts should be calculated relative to the 20% best natural background levels, similar to the approach used by NESCAUM, and as noted in the BART rule preamble. This is notwithstanding EPA’s allowance for states to chose the annual levels. 13 As noted above, the FLMs acceptance of the use of a single year of “hybrid” meteorological data is also contingent on the use of these background conditions.

The NESCAUM document on determining natural background levels references EPA’s guidance on the subject and also provides an alternative approach to the EPA “default” assumptions and calculations 14 . This alternative scheme updates the calculation of the extinction coefficient which is in line with the formula recommended in the FLAG guidance. This is the “new” IMPROVE equation used for extinction coefficient calculations, with the corresponding input parameters as defined in the 6/27/08 FLAG revised document (see footnote 4). The main input parameters recommended by the NPS/FLM representing 20% best natural conditions as input to the CALPOST program to calculate relative BART source impacts for the pre and post BART emissions at the Class I areas are provided in the following table:

Class I Area-20% Best Natural Conditions (NH 4 ) 2 SO 4 μg/m 3 NH 4 NO 3 μg/m 3 OM μg/m 3 EC μg/m 3 Soil μg/m 3 CM μg/m 3 Sea Salt μg/m 3 Rayleigh Mm -1

Lye Brook Wilderness, VT 0.05 0.03 0.36 0.01 0.09 0.63 0.01 11 Brigantine Wilderness, NJ 0. 12 0.04 0.86 0.01 0.24 1.73 0.04 12 Acadia National Park, ME 0.09 0.03 0.68 0.01 0.10 0.94 0.03 12 Great Gulf and Presidential Range Wilderness NH 0.09 0.04 0.56 0.01 0.10 1.05 0.02 11

Dolly Sods and Otter Creek Wilderness, WV 0.10 0.05 0.80 0.01 0.17 0.96 0.01 10

Additional input data, such as the monthly relative humidity factors, are also presented in the FLAG document and should be used. One further clarification needs to be made with respect to the CALPOST program to be used in generating the visibility impacts. Although EPA identified CALPOST version 5.8 as the “official” EPA recognized version for general use, that version does not provide visibility impacts per the latest FLM/EPA specifications and must be further post processed. However, FLMs have recommended the use of CALPOST Version 6.221 (Method 8, Mode 5) which performs the correct calculations with the new IMPROVE equation.-9- This version of CALPOST also includes more accurate calculations of the new IMPROVE equation than the VISTAS spreadsheet used previously in BART analysis. Thus, we recommend that this version of CALPOST be applied and the FLAG switch chosen which automatically sets the parameters to correspond to Method 8, Mode 5 of the model.

These data should allow the calculation of the pre and post BART control alternatives and emissions relative to natural background values which are the aim of the regional haze reduction program. These will allow NYSDEC staff to determine the efficacy of the control measure which bests fit the requirements of the regional visibility improvements due to sources which have been identified to cause or contribute to Class I visibility degradation.

5) Pollutants and Emission Rates. The BART Guidelines, as well as a follow-up EPA’s internal memorandum (in footnote 9), recommend modeling the emissions of NOx, SO 2 and direct PM in concert in the CALPUFF analysis to account for the nonlinear chemical interaction of these pollutants and their species. The emissions of PM should include both PM10 and PM2.5 emissions. In instances where a source does not have information on PM2.5 emissions (i.e. condensible fraction), references ava ilable thought EPA (AP-42 factors) or on NPS’s webpage could be used (see FLAG report guidance) . The relative contribution of the individual pollutants to the total visibility impacts in terms of deciview measure should be presented to allow the determination of relative significance of the pollutant emissions and possible control measures. The emission rates which must be used for New York source assessments are the maximum actual daily values which are representative of the source’s normal operations (excluding only startup and shut down conditions). As noted in the Preamble to the BART rule, the use of average daily actual rate could easily underestimate the daily maximum visibility projections and is not recommended. The maximum 24 hour actual source emissions should be determined by each source, using data over the last 5 years of representative operations, and demonstrate to the satisfaction of NYSDEC st aff as appropriate before any modeling is submitted. The BART guidelines note that this maximum rate can be representative of the highest emitting day of the meteorological period used. However, we do not follow this approach since the meteorological period covers only the single year 2002 and, more importantly, maximum daily actual rates should be defined a priori to the determination of maximum visibility impacts and not in reverse.

We recognize that there are hourly emission data available for certain of the BART eligible sources and for certain pollutants (i.e. EGUs for NOx and SO 2 ) and some of this was used in the NESCAUM preliminary analysis. Although hourly emission data might be more reflective of the corresponding short term aspects on visibility impacts, we are not recommending its use within this “default” protocol set of conditions. In order for such emissions to properly represent the potential visibility impacts under all set of meteorological conditions simulated within CALPUFF, these emissions must be shown to be consistent and static with both daily operations as well as seasonal fluctuations during a long term period of operations of a facility. We do not believe such a demonstration can be readily made by sources. On the other hand, if the BART-eligible sources do have certain demonstrated limitations on operations (such as “peaking” operations for a minor part of the year), these considerations-10- should be presented within the discussions of the set of modeling results recommended above (and any additional results a source chooses to submit) and the five factor analysis for BART determinations.

The emission rates as well as the stack parameters used in the NESCAUM modeling were submitted to each BART eligible source for confirmation and any revisions. These data verifications or modifications have been submitted and will be reviewed by DEC staff. In instances where the maximum daily emission rate for a pollutant cannot be determined, then the maximum allowable emission rate must be used in accord with EPA and DEC modeling guidelines.

III. Summary. Each of the New York sources subject to the BART requirements through the provisions of the Regional Haze rule must submit a net visibility improvement analysis at a set of federal Class I areas, identified previously by an initial modeling perform for NESCAUM sources. These assessments will assist NYSDEC staff in the determination of the appropriate source specific alternative for possible BART control measures. The analysis should follow the recommendations outlined in the sections above, with any minor deviations to be discussed with NYSDEC staff before implementation. Any signi ficant deviations from these recommendations will require the submission of a source specific analysis protocol which must be approved by NYSDEC staff, with input from USEPA Region II and the FLMs prior to submission of the visibility assessment.

### APPENDIX E

MODELING INPUT AND OUTPUT FILES